Franz Gross died suddenly during preparations for the meeting. He would have taken great pleasure in summarizing in this preface the aims and results of a gathering which so clearly bore his imprint as Chairman of the Scientific Program Committee. His sudden passing away is deeply regretted by all of us: organizers, speakers and participants. We greatly respect him for his exceptional abilities, his impact on science and his qualities as a human being. He provided the impulse for a well balanced and topical scientific program. We therefore dedicate the proceedings of this symposium to his memory. Munich was the fifth in a traditional line of